Emperor Hirohito of Japan was fully involved in international affairs including the daily running of the Japanese economy through the Zaibatsu families and their investments in Japanese industry. The Japanese cabinet facilitated this business group in Japan's ruling coalition from the september 18,1931 Manchurian invasion to the devastating attack on Pearl Harbour, Hawaii. The military conquest of Greater East Asia was directed by the chosen miliotary leader Tojo. The Zaibatsu regime extended their dominant position in the Japanese regime.
The Japanese had accomplished their conquests through decades of hard work, dedication to the Emperor and their nation and skillful management by the business leaders of Japan.
The rapid conquest of Greater East Asia was completed by 1942 when Guadalcanal was fought over between troopship transported Japanese and American troops. The endurance of the well equipped American troops on Guadalcanal and the interdiction of further Japanese reinforcements ensured an American victory which was followed by 82 amphibious landings to push the Japanese back to Okinawa.
The eventual occupation of Japan by US General MacArthur was aided by his willingness to allow Emperor Hirohoito to continue to rule with the Mitsui, Mitsubishi and Sumitomo families cartels suppressed and civilian rule continuing. Japan became an important ally of the US in peacetime.